Abstract

Risk factors for Toxoplasma gondii infection in workers and residents of swine farms were studied on 43 farms in Illinois. Blood samples were collected from 174 adults in 1993. The T. gondii seroprevalence was 31%. An interview was conducted with each participant, obtaining information on demographic characteristics and behaviors suspected to affect the risk of T. gondii infection. Factors associated with increased risk of T. gondii seropositivity were a higher number of seropositive cats trapped on the farm, male sex, rearing pigs on pasture, and gardening. Factors associated with a decreased risk were handling of pig feed and presence of cats inside the pig facilities. Thus, infection of cats with T. gondii increased the risk of human infection, and contact with soil was a likely mechanism for transmission. The increased risk of seropositivity in males is attributed to less attention paid to cleanliness in food preparation and eating.